§20 Sir george shuckburgh’s Obfervations 
On the azimuth 
circle. 
On the eauat. circle* 
C c by the iff obfervation, — * 
2 d, — — ■ 
0 tit 
9 39 0 
- 39 0 
0 / tr 
9 38 30 
- 3 8 >5 
3 d > — — 
- 3 8 45 
- 39 45 
4. taken four times over on the arch, — 
Mean, — — 
3 8 35 45 
9 3 8 5 6 1 
- 3 8 34 45 
9 38 41 | 
Mean of the two circles, =: 
9 ° 38' 48 y 
= t- at c. 
By attual obfervation. 
Angles finally corre£tc 4 > 
4 at a, 
— 58 28 43I ^ Thefe angles corre&ed by”! r§ 28 40I 
— — III C2 IO I W ;to each (the 1 ^ „ Jg* 
B> 111 *q- f fum of their errors, or 
Z. at C, — - — 9 3 ° 4*4 | defe£t, from 180 0 being 
J _ l8 ".) ' 
5 * 
9 3 8 544 
Sum of the three angles ~ 179 59 42 
Taken from 180 o o 
7 become, 
Sum, 180 o 
Leaves the difference zr 1 ^ 
fum of the errors, J 
It is highly curious and fatisfa&ory to fee the amazing 
correfpondency of thefe obfervations, made with an in- 
•ftrument of only 3^ inches radius, whereon an, angle of 
one minute is about equal inch; and I think we 
may fairly conclude, that the corrected mean refult of 
thefe obfervations is true to within 6" or 8"^; which, as 
(f) I may have a future occaiion to fpeak of the accuracy of this inftrument 
for aftronomical purpofes; but I cannot omit this opportunity of mentioning 
one, viz . in taking the latitude of the city of Amiens in Picardy, where I had 
thirteen obfervations by the {tars and Sun, the mean of which differed 25" from 
the extremes, and only 3" from the refult of Mr. Cassini’s obfervations, 
-made, I believe, with a nine- feet zenith fe£tor, as related in La Mtridienne is 
fyris verifies, 5 
may 
